Spreadsheet-based nonlinear analysis of in vitro release properties of a model drug from colloidal carriers

Analysis of in vitro dissolution profiles of encapsulated drugs usually involves the linearization of the applied mathematical model and sometimes transformation of the measured data. In this work, we demonstrate that a spreadsheet routine could provide a universal and reproducible data analysis strategy without the need for linearization. To test the evaluation method, different liposome-based drug carrier systems were prepared and characterized. Thereby, this work also demonstrates the preparation and characterization of size-controlled liposomes (LIPs) for encapsulation of the fluorescent Rhodamin-B (RhoB) as a drug model. During the experimental work different encapsulation- and size controlling techniques have been studied. The in vitro examined dissolutions of the fluorescent dye from the liposomal colloid systems were also presented in physiological environment. According to the evaluation of the release profiles we clearly established that, beside the appropriately chosen size controlling procedure, the remote loading encapsulation technique can increase the half-life of RhoB from 0.8 h to nearly two hours. Moreover, we highlighted the importance of application way of the chosen kinetic model. Explicitly, the coefficient of the determination-based choice of the appropriate mathematical model can be false if only the linearized forms are applied.